26 November 1922 marks what is arguably the most famous discovery in the history of archaeology. On that day, the British Egyptologist Howard Carter made a small hole through which he could insert a candle in the sealed doorway of Tutankhamun's burial chamber and thus lit the interior. As his eyes slowly adapted to the darkness, he was able to make out a chamber that had not been disturbed for over 3,000 years.

Tutankhamun was just an obscure pharaoh during his lifetime, and there is evidence that he was hastily buried – the second of the three nested coffins seems to have originally belonged to someone else. And yet the inner coffin, in which his mummy was discovered, is made of solid gold, weighing almost 250lbs (113kg). One can barely imagine how impressive the burials of such powerful leaders as Khufu, Thutmose III, or Rameses II must have been. Alas, they were all looted in antiquity.

But contrary to popular belief and cinematic glorification, most archaeologists would say that the search for spectacular treasures isn't their main research objective. They want to understand the daily life of past civilisations. Still, both extremes – the fabulous wealth of kings and the hardscrabble existence of common people – contribute to an understanding of what can be argued is one of the main goals of archaeology: to document and study the evolution of inequality in ancient societies. This also involves the question of how to recognise and quantify it.

One of the most obvious approaches would be through the assessment of differential goods deposited in graves. But richly furnished graves may not simply be evidence of social differentiation; rather, they may be an attempt to demonstrate the importance and distinction of a family in relationship to other kindreds – a social importance that may not exist in reality. Moreover, social stratification can be based on wealth but can also be based on personal prestige and power. Therefore, it isn't always possible to assess social differences by comparing graves with goods to those without them.

Some archaeologists have attempted to apply economic principles to examine social differences at specific sites and, crucially, compare the data from different places. A study led by Samuel Bowles from the Santa Fe Institute and published in Nature in 2017 tried to address this question by applying the Gini coefficient – a single number most commonly used to measure income inequality – across a large number of sites from the archaeological record, both in the Old World and the Americas.

You might also like:

The list of sites included paradigmatic cities such as Çatalhöyük in Turkey, Pompeii in Italy, and Teotihuacan in Mexico – the authors measured the dimensions of houses as estimated indicators of wealth.

Among modern hunter-gatherers, the team found, the Gini coefficient is low – around 17 (on a scale of 0 to 100). This is not surprising as few objects can be carried in nomadic societies, and consequently, personal qualities such as the ability to hunt count for more. This does not mean that some people didn't have a higher social status; material culture was probably so poor – or so different from our perceptions of status – that it is difficult to grasp social differences among past hunter-gatherers.

The archaeology of inequality